RESUMEN
AIM: The aim of this study was to investigate the interaction between the endothelin-1 (ET-1) and inducible NO synthase (iNOS) in anastomotic healing. METHODS: The expression of ET-1 and iNOS were investigated by immunohistochemistry in a rat end-to-end arterial anastomotic model. The aorta of 50 male Wistar rats was exposed, then transversely divided and re-anastomosed. The animals were sacrificed immediately after the operation (group A, control group), after 24 h (group B), on 7th postoperative day (group C), on 30th day (group D) and at 6 months (group E). Intima and media thickness and their ratio of the anastomotic segments in each group were calculated from computer digitized images of the individual sections. ET-1 and iNOS expression were measured on a semiquantitative scale ranging from 0 to 3. RESULTS: ET-1 was expressed from endothelial and smooth muscle cells (SMCs), while iNOs was expressed from SMCs and inflammatory cells. An intense expression of ET-1 was demonstrated mainly at 1 week and to a lesser degree at 1 month. Yet, at 6 months this expression was significantly weakened (P<0.001). In contrast, an intense iNOS expression was identified at 24 h, substantially regressing at statistical significant lower levels after 1 week (P<0.001). Bivariate correlation test showed a positive correlation between ET-1 and iNOS expression. CONCLUSION: ET-1 appears to play an important role in intimal thickening during anastomotic healing, especially in the late period of the process. Although there is a positive correlation between ET-1 and iNOS production, the activity of the latter is relatively limited after the first postanastomosis week.
